Causes

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Dust mites eat skin cells people have shed, and rather than drinking water, they absorb water from humidity in the atmosphere. They thrive in temperatures between 65 and 84 F (18.5 and 29 C) and a relative humidity higher than 50 percent.

House dust is easily trapped in the fibers of bed linens, furniture cushions and carpeting. These materials also hold moisture well. Consequently, bedrooms are ideal habitats for dust mites.

Dust also contains the feces and decaying bodies of dust mites, and it's the proteins present in this dust mite "debris" that are the culprit in dust mite allergy.

What causes the allergic reaction

Allergies occur when your immune system reacts to a foreign substance such as pollen, pet dander or dust mites.

Your immune system produces proteins known as antibodies. Some of these antibodies protect you from unwanted invaders that could make you sick or cause an infection. When you have allergies, your immune system makes antibodies that identify your particular allergen as something harmful, even though it isn't. When you inhale the allergen or come into contact with it, your immune system responds and produces an inflammatory response in your nasal passages or lungs. Prolonged or regular exposure to the allergen can cause the ongoing (chronic) inflammation associated with asthma.

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